Electrochemical sensing of 3,3’-Dichlorobiphenyl using green-synthesized gold nanoparticles and Polyvinylpyrrolidone composite

3,3’-Dichlorobiphenyl (PCB-11) is a persistent environmental pollutant with detrimental health impacts, requiring sensitive detection techniques. Its detection in water is of increasing environmental concern due to its classification as a non-legacy PCB associated with modern pigment manufacturing. Unlike legacy PCBs, PCB-11 continues to enter aquatic ecosystems through industrial discharge, despite global bans on PCB production. Its chemical stability and lipophilic nature contribute to environmental persistence and bioaccumulation in aquatic organisms, potentially impacting food webs and human health. The presence of PCB-11 in surface and wastewater samples underscores the limitations of conventional monitoring programs and calls for developing sensitive, targeted analytical methods to detect and quantify emerging contaminants in complex environmental matrices. This study reports the first-ever electrochemical detection of PCB-11 using a green-synthesized gold nanoparticle (AuNP) and polyvinyl pyrrolidone (PVP) composite. AuNPs were synthesized using guava leaf extract as a reducing agent using a sustainable approach, resulting in uniformly sized nanoparticles with enhanced antibacterial and electrochemical properties. The fabricated AuNP-PVP composite, deposited on an indium tin oxide (ITO) electrode, exhibited superior electrochemical activity and sensitivity, attributed to its high surface area and conductivity. Characterization via UV, XRD, FTIR, and TEM confirmed the structural integrity and nanoscale dimensions of the AuNPs. Differential pulse voltammetry (DPV) enabled the detection of PCB-11 with a limit of detection (LOD) of 0.4844 ng/L within a linear detection range of 0.625–80 ng/L. The sensor demonstrated exceptional selectivity against common interferents, ensuring reliable performance in complex environmental samples. The developed sensor offers simplicity, high sensitivity, and eco-compatibility, marking significant progress in green analytical chemistry and environmental monitoring. Graphical representation of synthesized gold nanoparticle via green chemistry followed by fabrication of electrode for electrochemical sensing of PCB 11.